Appendix A: RF Troubleshooting
Nokia Customer Care
Company Confidential
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2005 Nokia. All rights reserved
A-46
3.1.3.3.2.1 Low pass filter components R7509 and C7533 ok?
•
Check that components are in place and solder joints are ok
•
Disconnect the power supply from the phone and check R7509 resistance value with an
ohmmeter.
•
Use an ohmmeter to find out also if the AFC-line is short-circuited to the ground. If short-
circuit is found replace C7533. If this does not help then go to the next steps.
3.1.3.3.2.2 VCTCXO ok?
•
Remove R7509. If AFC-voltage is correct after removing then replace faulty VCTCXO G7501 and
solder R7509 (new component) back to the PWB
3.1.3.3.2.3 Replace Retu
3.1.3.3.3 Replace VCTCXO G7501
3.2 Does the phone give realistic RSSI-values?
Attach the phone to the product specific test jig and a signal generator to the RF-coupler. Coupler
attenuation should be also taken into account during measurements.
Use the signal generator to supply -90 dBm RF-level (unmodulated signal) to the phone via the
antenna coupler. Set generator RF-level to -90 dBm + cable and coupler attenuation. This
measurement should be performed in a RF-shielded environment because existing GSM-network
base stations can disturb this measurement otherwise.
•
Set RF-generator frequency as following:
-
GSM850: 881.66771MHz (Channel 190)
-
EGSM900: 942.46771 MHz (channel 37)
-
GSM1800: 1842.86771 MHz (channel 700)
-
GSM1900: 1960.06771 MHz (channel 661)
•
Use Phoenix testing & tuning software to perform GSM receiver activation and RSSI
measurement for proper channels. Procedure is explained in section “GSM RX chain activation
for manual measurements” (Start “Testing” -> “GSM” -> “RSSI Reading” tool in Phoenix. Select
the correct band and channel).
•
“RSSI Reading” -tool should show quite exact -90 dBm RSSI level. Remember to take into
account attenuation between the phone and signal generator. Test also Q and I branches
separately. Signal level in both I and Q lines should be about -93 dBm
•
Increase signal generator RF level to -60 dBm. Phoenix ”RSSI Reading” tool should show now
quite exact RSSI level -60 dBm. Test also Q and I branches separately. Signal level in both I and
Q lines should be about -63 dBm
Summary of Contents for RM-57
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